A radio census of nuclear activity in nearby galaxies

• Type: Article in International Scientific Journal
• Date: 2006

Authors

Mercedes E Filho (Author) FCUP; Barthel, PD (Author) Other; Ho, LC (Author) Other

Journal

Title: Astronomy and Astrophysics

Vol. 451

Pages: 71-83

ISSN: 0004-6361

Publisher: EDP Sciences

Indexing

ISI Web of Knowledge - 52 Citations

Scopus - 53 Citations

Other information

Authenticus ID: P-004-KV4

DOI: 10.1051/0004-6361:20054510

Abstract (EN): In order to determine the incidence of black hole accretion-driven nuclear activity in nearby galaxies, as manifested by their radio emission, we have carried out a high-resolution Multi-Element Radio-Linked Interferometer Network (MERLIN) survey of LINERs and composite LINER/HII galaxies from a complete magnitude-limited sample of bright nearby galaxies (Palomar sample) with unknown arcsecond-scale radio properties. There are fifteen radio detections, of which three are new subarcsecond-scale radio core detections, all being candidate AGN. The detected galaxies supplement the already known low-luminosity AGN - low-luminosity Seyferts, LINERs and composite LINER/HII galaxies - in the Palomar sample. Combining all radio-detected Seyferts, LINERs and composite LINER/HII galaxies (LTS sources), we obtain an overall radio detection rate of 54% (22% of all bright nearby galaxies) and we estimate that at least similar to 50% (similar to 20% of all bright nearby galaxies) are true AGN. The radio powers of the LTS galaxies allow the construction of a local radio luminosity function. By comparing the luminosity function with those of selected moderate-redshift AGN, selected from the 2dF/NVSS survey, we find that LTS sources naturally extend the RLF of powerful AGN down to powers of about 10 times that of Sgr A*.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13